The present disclosure relates to an optical scanning device, an image forming apparatus using this optical scanning device and an abnormality detection method for optical scanning device.
There is known an image forming apparatus for forming an image by deflecting a light beam irradiated from a semiconductor laser by a polygon mirror to scan a photoconductive drum and forming an electrostatic latent image on the circumferential surface of the photoconductive drum. There is also known a technology for introducing a part of a light beam output from such a semiconductor laser to a photodiode by a half mirror, detecting the light quantity of the light beam by the photodiode and displaying a message notifying that the semiconductor has failed if the detected light quantity is below a specified value.
However, in the above technology, the presence or absence of a failure is determined based on whether or not the light quantity of the light beam exceeds the specified value. Thus, even if a failure was judged, it could not be discriminated whether the cause of the failure was because the semiconductor had emitted no light at all or because the light quantity had decreased due to deterioration. Further, in the above technology, the light beam is introduced to the photodiode by the half mirror provided between the semiconductor laser and the polygon mirror. Thus, there has been an inconvenience that an abnormality in a scanning operation such as a misalignment of a scanning position of the light beam reflected by the polygon mirror cannot be detected although a failure of the semiconductor laser can be detected,
An object of the present disclosure is to provide an optical scanning device capable of determining the content of an abnormality having occurred in an optical scanning device in more detail, an image forming apparatus using this and an abnormality detection method for optical scanning device.